SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48fcd778d97bde6c968a911764e52fc181050c09e4e8088d9115de325ebe64de' 
  AND token = '296SnwF54zZgX+OqJNVGubbmgwJpx7mqK+iiDyh+nx8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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