SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92d519c4cf15aec9908fe5e7d38b3c72ba857a8a40276fd1b3c70bdc0708b543' 
  AND token = 'o9UKf4FJC4IjqGijpUIJBzgLryQ7EzH1xH/f1QxlonI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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