SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49369749dfb614c38edd443313fa19ef6b888a32a6a0194882c821d9b2be94f9' 
  AND token = 'PBSJLm0+SECMt5qjCjFGnDuu0lUkfsJmnFtVKKV5ysA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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