SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3b65da7ef344995934e4c965a3fb9466a95eef3281a74902e9dd2b778d102f4' 
  AND token = 'xJtx0YNqJ6udbiei54fesBld0Ficeaj31rf//OuDEdg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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