SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb575d98f824a5c940c24cbb5b3120616a89701cb4dbf88461f4cc89526f1795' 
  AND token = 'hFwTPuq6Dgzl4plXizhPE/tiAVOFPhdFSi81FDCAGpU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}