SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d2b2d7da3019e8e095f23e2a6f68443a1c65e019c2e363180340afd2554b0b9' 
  AND token = 'xiB4GiXKztAXBL8jvOUIoCjvHw2+jK4Ai7zP9qzdmpI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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