SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '560475e50cbcf16cc0a0f613f6aaf38bb89d407b25dd56f4814d372b23ab7690' 
  AND token = 'yQz3qUcKdqhb3/hiPjmi7kjGcQp60v6KMQK7Y+Szr3Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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