SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1602ad4c852f40de660e8d47ae151e0fe90df908538beb53596d715c80e76747' 
  AND token = 'xNvgmW2kUlMt6j748MizVGklfMExx+VSdRyEy3H+XCU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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