SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d8ae3881320732b5bf3512592ceb4ef16c8380822fd9dfb59ce2580c238698f' 
  AND token = 'CWTTJf7urVb8KlN//a3GVgMZt0U2Q6+jKlFrU/CmNAs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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