SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91cba8a838b121ad52162649407913fce1c946951df038ff53e2dd37f4de946f' 
  AND token = 'Y5fJSdUP0emeIWMCrwKqzQkmQxQXVVin9DA7y9+Dbm8=' 
  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"
    }
  }
}