SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e840e3ac89ef396e79b9fb2b0a95a10849752ba5b5a57bcf5e39aacff7769e9' 
  AND token = 'mEzOYN5oKsHbEUCTmcJgwxCicyIPsLx6wBstrckBra8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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