SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f570294004bbdf0af8836c06177bae00efb7a431f8c29e81c0099169f88ed1e' 
  AND token = 'A4yaOoU1NDmToe9aSyPcxBvUiSq6NSO0nrSc/0Pr5+c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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