SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9cde4888193f10073e6effb71b27c05af530411735870f1012d3d00947a6a0b6' 
  AND token = 'yuUraVMTV0MGYxsG3C1ZCgB3pa+VERUXQDRtUwlMYJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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