SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6820c63ea39cd18b16716f7cb34253c7b44d2f258057369bf04d511b925fcbb0' 
  AND token = 'O0/pjTiQVrOHuKvZTalxcNovd1T8eWNGng3K+ywKD0E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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