SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b1ff8f87c92538bff1381637cba57d35a440e3db536039105e936447cbb6b2b' 
  AND token = 'QKrXNkU8HG+B8b1uj7v4jNUHVfQncBhMBSFT5bU8V6c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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