SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4874129668b4dee654b1656fe9cc525f191732a3571bc322aeb4979a0087c10' 
  AND token = 'P1nJgvbxUc8tCl0LMkIWeF2PctLEwYROnI7WHwoGNk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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