SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2bcc2d1ca112b5a5acac593864c6e056a451551f5fc8861c7c50604ac87fddd' 
  AND token = '/JkG90NQsz+lZvM4Ly2xXHuU50VKn9jJBnqYHvteKA8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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