SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b77fe45442ce97d10598d2802a63d06fb0c6a589b5e52945e62cfb15b21c11e' 
  AND token = 'M+FxXSOWlzCV4LeNfhPHcPP7lOf7cQsx0PgQSOLGlk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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