SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23db1c7e657c97a71113027cb50853df191e3abd22f2cc90a52debeeeb8c947a' 
  AND token = 'QHUpDpPNQWi8VnR+/w1HYCH4QcRGGGJgLZJvCYCjhC8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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