SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c9e1bb74372e3f6eb64db9a78c114d54d1e0450c2acbc081b719ecf48a660db' 
  AND token = 'oGa3fjJTs83zMGfGz5l3w24dfPFrBXgAc5Cc8AxTFrw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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