SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '503b7b74dbd680a65db813d388de043f983b14bb59db1b11716f743eb34d927a' 
  AND token = 'tVJvwHFlg5y/MwYU2ypqPj2/3jvhqNHeLA/AsNlDlrE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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