SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca434a42e00e7bf67ec6b41142fb248ad504f01d623dd9df50842e3e8df4317d' 
  AND token = 'WzlBEHSm/Wb0J/dsVKfnP1ClpCgvseWFopF8NNkPKdM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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