SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8761bd33dbcac30a56aa9a9467f15f1f0bf3488e06094fa7881bcd1bc5165a18' 
  AND token = 'CkAzdgv22S8kBuPklb0YsU3Sqo/OolzZwxH5c16/YXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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