SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f127b9ea4e86e25029cf2f28239db7aa5567751e57a8c94f74bffefb182b306' 
  AND token = 'ruKQuLccQUh9pModG3zIyUoGSl3ZYcZy/L+RSIXmcBk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}