SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14f7923823187d806d3ddf29c56804e9e5c89a0509c94313f376bbe42b8d824b' 
  AND token = '7v+f1Ib9N1sIKZg9rpBaXaRzQHf3uRaYHQTJ60UWUjA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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