SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fd540f3f1d0cac844e12a44379b3de156ec59f0930960f606089a049655d3e7' 
  AND token = 'kdqVrhmJQVKEKwQEthwKtMYVfXOveDowDXPjZEnXXNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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