SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9656dd6ff0796585b95e8a47bd0497ebefea356334df71917afa63efb79d140' 
  AND token = 'coKLrriSXOXcFTDzKfCv0qSPeRiQjU5wzo2wkpiRa6Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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