SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ff99f032f1fb2010835817389d9f0a8a1019381617e5ebb32ee310a5a1f15b0' 
  AND token = 'gBooYXik5EHOshoYLZqLcf7XgYYOCwWDrG7bYe/wQq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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