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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6e8a9c0dbce46b54fe2fe5803492df78af12f79c871734c5c26bdf32fa9f285' 
  AND token = 'Rt2137trTjZRakAnHSwOKf+town/ot3nQswi9AMhVbI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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