SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '338fa95d808b9cfde007070f06883c633a79ea2053eaf3f70263cc0e9ea603d9' 
  AND token = 'ZVdR3dXHdoQzOjfYtfELjeNMbwXRGlKIRxTogADhkgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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