SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0758fa5e73f9a0a20177fac9870f339690792e4b17ac3456131053f3ef9cca9' 
  AND token = 'jG3CdhMG2X+/cj8oxF4oejDwQrYeTs3LEcAfNQ6kMQM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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