SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29a978af8085a20465924a7add59788953addde6a9dad6ceed9562f20f555c92' 
  AND token = 'Jvg9bBWhYgyaIrZygGHp7FYLUny31OUqWe206t/sAlQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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