SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c647fe27af470beb975ab26c0dd1a25bf3d633f5fb84d60e06d1f132503ade7e' 
  AND token = 'ApjwfCMsYnDC6BuqldVUF/Bqbn8dn5UNT+qZfkBtIHM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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