SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b45a21522db26bf1bedc8a7af9581f512e57441e73e4fafd7d172943d3ede6bb' 
  AND token = 'J5j7GWHsxMthd+/3gv1ArDsNyYwwuwxpJqSZSkI0XCA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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