SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '496a82fed25d55d69ffa7ec966795aa5e1def9cfabb94ca7395c53f84ef30fdc' 
  AND token = 'W/kNAUS7RNGzGv5UTMum9qhcvdMsCQdm80mzHQZyXoU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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