SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a07872a4142f47053ae538d93f540c2acd266b90a1487618e8b4863542be3682' 
  AND token = 'R+Adc8mH9+ZyHIUlWkGumM0GWfDJEAtm0HhtDYWMcu8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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