SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c6c606a1bc1327206665855db0e80c186329518f0ba21efd48ee24f1e7ff583' 
  AND token = '9JMhwGkyRn4i9b9PLQx5KeW7qNwOLzSoOGtChO5d/gs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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