SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9f617be4a598e5e9edc7e03a8cd74460f5fe8e7c5343efb0f127f74704d07f5' 
  AND token = 'SyYams8l7KP2JGiuSOYKH/dziQWpoKKraWqTlUY3OHI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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