SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc5412a822e22b95e843b5699a6fc69b1903737f0306333c045adbd97b956451' 
  AND token = 'hCeDFYul17Ja9Lk0Dnnxvh4M/wxJ3wvlL7PvTGBJbY8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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