SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afef085b737f33362537535be0ff7794590158aab30ecb7092b4e7dafbec2549' 
  AND token = 'AMnq0pI2sCQfWMWfg9THR5kiIz0To1oAqBCt+RiA87c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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