SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3800ce2f3071797929efa25cd3037289b910558637170ceec029d2dbd13ec021' 
  AND token = 'dazc54YwVlVbcWvBLMKJ+39mWhM0DZyvYIp5s9FtYxk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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