SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e5465bdf42dc5750e6635e7abfeedc8caf2ac66994f23781517319bfed11433' 
  AND token = 'Am6eiwFcftILNX3sMS0IgfNkT49qxqXhjUPMDIh2Xwk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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