SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '373b32312ad806463dd1fb9bf21c3236f296625f8b0c6c25538459727a844577' 
  AND token = 'yxDZhOBslhWTUyd+J2a8sBazlGJPaIzAgqD6EcbV5VQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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