SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77861cabfafb49e96d3fcb6e7c27d96bd15d23abfe56af3a74189dc554a5b770' 
  AND token = 'm/d+C+PRbqutTw10SghURBZBYUyJwet44rLE4mnbUyc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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