SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84902bf77b8572758150570bfe70015e90ae71eee79622093c9c04eeb445232d' 
  AND token = 'XTdeywBSMsPCbMtEtV9afuIHWPaQl86xeHi1F1QUQNI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00066

JSON explain

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