SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd4657d52f8b51d1729db45a65c4b528a2b22aaa58d474e87f7f0f93e05f4512' 
  AND token = 'MnBBF/pncZmmJ3ecre3XFn3yksnej6VryKwZcsljtv8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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