SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '903a26cca56568da29df8535e79bcda1d16679fcddbaf087ec780e657e14437c' 
  AND token = 'XiIiI97H36LkNFhgZade8kmOzMXcEJtlN+LEDvecAf8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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