SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3349bf92aa8b0a494de5c9bfa26c459e90d81ad2059db33b4eafa0a64042cc1e' 
  AND token = 'kjHMpF990XhqDerJBAgAeF2RW0txfWZYfEhBDC1OkmY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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