SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3071788beceba9343c1f57e8642d79df33e3477c5fd70c01ffccd58b333fd1eb' 
  AND token = 'SRE1OLWd5OlWEXhd6agpF77ugueCTaweoBUdjdAAvo0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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