SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85cc9112fa605c8b75797b21474bda94a6466ba68fbcc74e082e21c1866496dd' 
  AND token = '3dorTviAVe/bqmkCiWlMUP499MIgeaVb6DXC14hnqMk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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