SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4ce029a9b2437dfdf2058928e5724cd38f212a72db1db661475bf13ed59794b' 
  AND token = 'KZuHiNMWyZN0tPEbOarKZQFMdVEdiX5XW1awvMMLK2M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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