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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37e4900a2b1fd389b45adc18b9b15248645fc4fcf3871a3c5994ee697eafa324' 
  AND token = 'R2NeHz5ds8K2o7WIiwo1BSCd/cWJmuh1RHIz5Vfh/8c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}