SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f4470e4f05360e6ea40f236efb2a387bb37c0cf9d0cdb33c453b57325c17cb7' 
  AND token = 'luF1xfSuv8Vv7cMJQm6Uh8iZLLlKjB/NKnv1ZEqU9E0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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