SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd468555ac0bbe99265f22526233624d6f4da827f005c6b0894f2fdb098cfdbeb' 
  AND token = 'eWkyxK+X3arcGiboUEwKHjzFQJBCTCkzFMwdRSf2oxE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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