SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fdcd37f8c84c5cf023eb98df3fef4ee052a09508dd4b79ec589d547c8a9ad81' 
  AND token = 'M3s/xrxVdN+mYcZGfY+wybR9NC+fwXJHtk8CiWShxW8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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