SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8cb9f23c81223f211c90abafe3708a1dd8dac0f8806719c075756b40f74ab89' 
  AND token = 'pfJkyUcF2xIxgItsGPqsHVujpPXk7WzqRJ9a3BBsEXA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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