SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36fd53202277dfdf9b8dc6af12dad6362431ffd36a0af2b281ad7cff5b329bd3' 
  AND token = 'gqCq1AV9SiFLguq6WfObBYk9UdARVAKEdIXsWLFlr98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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