SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c10ca1e232f6b015ce4236fee9e9537837aa9d99206652e6d9b5421110136748' 
  AND token = 'rKWIzp4V1TJHToT21sFG/mp7GrgzYEW/PgbwB9BYjOo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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