SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ebb23c50e171f05510284563c09424f4a50ddcfb163294e7126058edea068683' 
  AND token = 'zhMtRqEZ2Avof8Daa3U2SaynWonUscfY8g9LogRjV1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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