SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '673416ddfcbe3a4e4c574ef3b50573d0179e8cb36d26522b13932fdf9a32fdbd' 
  AND token = '31lklSbuVG97SOkqbkJKyJg/RZuwLlKscll+xGyGuSs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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