SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f114da7b444cc8c473c65d7f294c09bdb9cb761afdec6618cc72aea7afd88ed' 
  AND token = 'ELpAop1l1gt30ouJrBwRTk8rV7mNGI6EvDHoMB5N74M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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