SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8523af4cda5b1cccf10bbda5316932dfcad8d42d7f8826f40215e32b1a104bd' 
  AND token = 'VzqNbXUK3pnZ1RiXCS+ZMa3qVO8Edqhqsnk4gRbQsPE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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