SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec531db93898673dd29d6e2ac406be76528683708d8055b3c9834cf864179ef0' 
  AND token = 'Q2hsHdXM/Vd9TMfRqp7OqTVC0Qr3KUGPTNp+RInK5m4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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