SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcba6a3024107e2ad6f70e9bee4973c1a83518bd2c3e7dd793cb6b49372a2894' 
  AND token = 'cbh/gChcV48eQ1x7JJYidUBHXe6WydpowQADr0LJsgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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