SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b04b0ef6f4c911bc9c11129459b121e2ad5d6f09609c2507d45eadd257351c1' 
  AND token = 'uNuN7lEGBDw7eYuSWoAB1Xp5aNPKcGvr28MWWb3DG/g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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