SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c82e74b04578af946fed81fedb02107e90f1816f5c74499919917450de0fa8ef' 
  AND token = 'D8EeKuWHjnrxvJkKakYcjJ16sAuzgQul2nslhnM1XUU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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