SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2da8ad5db26c4662df074f36a9ab598823290cf623295d0ebdd546d660201c7' 
  AND token = 'mCm3HOeF8LTiUwqQ50/4Hm0+s1lxUROST2XxqIagVrw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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