SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f00f53ae1986678284c1eb55f40fe476d232e58f739c95e71aa9b6f43140204' 
  AND token = 'BmFW+kOM34ivJaVWU5gypdx0IEYKo2cKdPsvNiqsL0k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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