SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '04f8c1be609578850387ded4a83326cc280d4c801fc5bde16c14b4311e1ea514' 
  AND token = 'mLFfVqc8uUnsp7SmFkGPdRwoKeJrnVawwPO0A+VZtFw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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