SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '828d3908cf77668cc220bb772b15956f0c206a646a9ddd5a4cccd2459016426d' 
  AND token = 'u9rUtl3K5cVaWTwBXpHsZUOYV1Iei0pkU9nwhxeHAZs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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