SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fbd8f19d5cdb79dffda4bf7f50836ab06873fb7353ac266c5744a1751ffeb83' 
  AND token = '7hDLKtJr7+5Ngkbj7i39CH1C6vPsQloBqEnMxf0nKK4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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