SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a262338b505ab3da1cade393946efd5dfc2a5f3c3af3b7803aa7d6e6bf044c5' 
  AND token = 'beFmxphtnd15CE4D9+uYgRdyUO7kd0/qmOZVQSjnTS0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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