SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9b6a91f66d91f5ef8d5612c5577540c9d3027bc9663343afecc425f353296f6' 
  AND token = '4mK2Stvv8+J/iquwjQNTJFjLEItLoZ0rHjKVyxJjBn0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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