SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0e411409920fa6369c31ce60f7d10369b3ddd0508002a671e4287e7ce97c3eb' 
  AND token = 'EKPdyf2THeUAgMlSpuE61H8jdl5qkfAPBnDnSkoUPGs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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