SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '619d94888bbe3530025d55aea5e939559768215da149dd3746903c0e54f27186' 
  AND token = 'm9M1wwy4WyXZOWZHsosjFA/+JhNuwqMzGOFTmceKi7c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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