SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84c81ebd6fd5ef2db659fcc275856cb3bb14f970d7a2b0b928d31c66f2e849f4' 
  AND token = 'PYT0G7kIqmdc9eN5hxyTXSVt8/YkhtxE0RPst8oEJzs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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