SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27d7c19a15b67ff0b6b2bfc1310d81601b455665c97d1c6676c6cb463068677e' 
  AND token = 'p7IGlSXDgFOQ5QQHAW0Qsp9mPWMZ6GrbkcxLrxTsDr0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}