SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f7bf322b36c7f179e6d243bb1e5c70d30438c835a4f6f78145bca77e1d4612c' 
  AND token = 'dlPyT3uPHVwL+tfXx5ch8AAKCGnGHwH5CBaFrB6sjGQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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