SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a979dbc00f7af369b3583c019cab43feeab2a90abadf6db34550da386d0c08d' 
  AND token = 'Wu1H58+mozrXTo3szDvk/MxFNPxdIqmCuMlUuR7PA3g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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