SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d27deed7499931210ec8939483aa4d3526197253129ac087fcc79844b87821e' 
  AND token = 'UO6xWmrKpWgk8tzcPeRqCQlEdX294zTQv8/wzj8xcbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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