SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce7b2321e84e2a87e4be508731cd859c21d3b66cfa9dd2c7c3d52e823d85891b' 
  AND token = 'sSCKKmq9v39ioz8v1UsuU7hZhMewuEZAKU4uIa2zqIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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