SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ddc4349a328c51eafae7b1d3645410bea335de664135f4cc4b3414896f895f5' 
  AND token = '89j+cwoFRkehEGpslsyf931rrJbCLNkfJEfNs9l6r5o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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