SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8be3726a8460aef4a4b539aee448dd2725ecb3d2825b897825165b2199c925b' 
  AND token = 'cvgJim9ueM7mMg1IKTqmKBz6Pxo5zzvbiM+kIwhWWHo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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