SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8478ea39696b721872bcbe152345cb581d25074c9e5e315d7c29916f500f5c87' 
  AND token = 'W1iSceTtFQ4NNq8LGCvdcFeZWF5oWemUD0hU8M5kyHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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