SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28e8d47088825b482865588ba51ad3e10c3bbd5a8be465ca57e576453efaf700' 
  AND token = 'KUx6ru8IkChXectGSJ2QJmosvKIqsx4B+Xsua8XTKvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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