SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c7fdfe7ad1af6abc2565af5930dbe21cfe96c5be726675cac590172547e7755' 
  AND token = 'uJsRbVNUAPkswTrh9TMSARgjOKjulyNnHtJEb7aRimE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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