SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bb98cfd7352cd1e6fc1bdc32fe62fcecf43b64dd308e4780813268ba28f5da8' 
  AND token = 'NXvBkhu4YmV6NJZs3L+gG+huWgrsUeJgq6hR3ElNMOk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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