SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0548eb8a96452d2b4574b835b2f7e2eca8d5ceaa559708c708e40e6422d1a414' 
  AND token = 'l/ueEoU3g0MnhQZs1R0uXqMrqZgjV27+C23AatkNi7g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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