SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8dbea7aa2f9c15f8a6dae5c6ec44a075683c4ba268d3e8c5f39746184b5dd574' 
  AND token = 'cajxjqdEfpkdDBHAmT1o/XuMp6+9i50pKANp1UH6DTk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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