SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '419c7bf3dc575577657b4467f4d3083c828d481971ad6c26761b9ed1109b79f7' 
  AND token = 'bIzn0wXbjihihx+KgPUxc6ZgK7zy3dYAjhWDFffgPW8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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