SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e9ca8544ed188954a4a8160344899835799c0a2735a65e3c8b935576ddc1fa8' 
  AND token = 'KlV5ne/h7Uw+B4fA9/BwTgYpFJBgjivKx/3qwDhs8gc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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