SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa3188b1023b4e6bcac6b367739458ffd1a7c3446cf650d5f59249813dd73def' 
  AND token = 'm4LlzEzPWZ+B/AgYeuLO4De7jP3xMuM+Vy4eJqiRHUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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