SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '446352fddb82bbcb0edd96f84d4a721a58a8017e6e35ac357083f0ef81fbf817' 
  AND token = '0Zdfv7ejtBdJ1xTJySQhwRwcPVqYLVBtEFO6FHeNHLE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00123

JSON explain

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