SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ace20d66541fdd8126d7dfc87b87d00c29ddb2071e0403dd141583e9a781745f' 
  AND token = 'aVeGfflgezDBwHfNyffwwkemTcUSleITJy0174MWoUA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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