SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cbcb318217f9c43707af9a27369e13526661b636e33e862354431dd11fae3afd' 
  AND token = 'IdtqEw/qP9VTZBulzrGDbIbjCILvBgq/2k5n+5BLu/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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