SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc481dc223330b404b19bbdb17da65b01fec1050ec8fb5b20608d45d14368c4b' 
  AND token = 'tjQQF3cMySiNgFWQm7f/7NXSxZFEq7SYKoU+BRLKyoQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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