SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0aaa0a5585f709ba227ba356fa84501de8bb9e35e921d7401ce75cc4c7f91c1f' 
  AND token = 'yLTiPQd9F6GTPRqms/td3OouIDdqvEqyzYuXJen9dSA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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