SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5a413cc5efda2c527c798bdb45717f474e00ab1770d8982835df6daa6108440' 
  AND token = 'tDHleJBiyj0nATHwe4G8ypyl8vWXuiFjShhap5uQ1s8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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